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Java example source code file (subnode.cpp)

This example Java source code file (subnode.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

boolnode, node, null, op_addi, op_addl, phasetransform, subinode, type, type::top, type\:\:double, type\:\:doublecon, typeint\:\:cc, typeint\:\:cc_gt, typeint\:\:zero

The subnode.cpp Java example source code

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "compiler/compileLog.hpp"
#include "memory/allocation.inline.hpp"
#include "opto/addnode.hpp"
#include "opto/callnode.hpp"
#include "opto/cfgnode.hpp"
#include "opto/connode.hpp"
#include "opto/loopnode.hpp"
#include "opto/matcher.hpp"
#include "opto/mulnode.hpp"
#include "opto/opcodes.hpp"
#include "opto/phaseX.hpp"
#include "opto/subnode.hpp"
#include "runtime/sharedRuntime.hpp"

// Portions of code courtesy of Clifford Click

// Optimization - Graph Style

#include "math.h"

//=============================================================================
//------------------------------Identity---------------------------------------
// If right input is a constant 0, return the left input.
Node *SubNode::Identity( PhaseTransform *phase ) {
  assert(in(1) != this, "Must already have called Value");
  assert(in(2) != this, "Must already have called Value");

  // Remove double negation
  const Type *zero = add_id();
  if( phase->type( in(1) )->higher_equal( zero ) &&
      in(2)->Opcode() == Opcode() &&
      phase->type( in(2)->in(1) )->higher_equal( zero ) ) {
    return in(2)->in(2);
  }

  // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y
  if( in(1)->Opcode() == Op_AddI ) {
    if( phase->eqv(in(1)->in(2),in(2)) )
      return in(1)->in(1);
    if (phase->eqv(in(1)->in(1),in(2)))
      return in(1)->in(2);

    // Also catch: "(X + Opaque2(Y)) - Y".  In this case, 'Y' is a loop-varying
    // trip counter and X is likely to be loop-invariant (that's how O2 Nodes
    // are originally used, although the optimizer sometimes jiggers things).
    // This folding through an O2 removes a loop-exit use of a loop-varying
    // value and generally lowers register pressure in and around the loop.
    if( in(1)->in(2)->Opcode() == Op_Opaque2 &&
        phase->eqv(in(1)->in(2)->in(1),in(2)) )
      return in(1)->in(1);
  }

  return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this;
}

//------------------------------Value------------------------------------------
// A subtract node differences it's two inputs.
const Type *SubNode::Value( PhaseTransform *phase ) const {
  const Node* in1 = in(1);
  const Node* in2 = in(2);
  // Either input is TOP ==> the result is TOP
  const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  if( t1 == Type::TOP ) return Type::TOP;
  const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  if( t2 == Type::TOP ) return Type::TOP;

  // Not correct for SubFnode and AddFNode (must check for infinity)
  // Equal?  Subtract is zero
  if (in1->eqv_uncast(in2))  return add_id();

  // Either input is BOTTOM ==> the result is the local BOTTOM
  if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
    return bottom_type();

  return sub(t1,t2);            // Local flavor of type subtraction

}

//=============================================================================

//------------------------------Helper function--------------------------------
static bool ok_to_convert(Node* inc, Node* iv) {
    // Do not collapse (x+c0)-y if "+" is a loop increment, because the
    // "-" is loop invariant and collapsing extends the live-range of "x"
    // to overlap with the "+", forcing another register to be used in
    // the loop.
    // This test will be clearer with '&&' (apply DeMorgan's rule)
    // but I like the early cutouts that happen here.
    const PhiNode *phi;
    if( ( !inc->in(1)->is_Phi() ||
          !(phi=inc->in(1)->as_Phi()) ||
          phi->is_copy() ||
          !phi->region()->is_CountedLoop() ||
          inc != phi->region()->as_CountedLoop()->incr() )
       &&
        // Do not collapse (x+c0)-iv if "iv" is a loop induction variable,
        // because "x" maybe invariant.
        ( !iv->is_loop_iv() )
      ) {
      return true;
    } else {
      return false;
    }
}
//------------------------------Ideal------------------------------------------
Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
  Node *in1 = in(1);
  Node *in2 = in(2);
  uint op1 = in1->Opcode();
  uint op2 = in2->Opcode();

#ifdef ASSERT
  // Check for dead loop
  if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
      ( op1 == Op_AddI || op1 == Op_SubI ) &&
      ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
        phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1 ) ) )
    assert(false, "dead loop in SubINode::Ideal");
#endif

  const Type *t2 = phase->type( in2 );
  if( t2 == Type::TOP ) return NULL;
  // Convert "x-c0" into "x+ -c0".
  if( t2->base() == Type::Int ){        // Might be bottom or top...
    const TypeInt *i = t2->is_int();
    if( i->is_con() )
      return new (phase->C) AddINode(in1, phase->intcon(-i->get_con()));
  }

  // Convert "(x+c0) - y" into (x-y) + c0"
  // Do not collapse (x+c0)-y if "+" is a loop increment or
  // if "y" is a loop induction variable.
  if( op1 == Op_AddI && ok_to_convert(in1, in2) ) {
    const Type *tadd = phase->type( in1->in(2) );
    if( tadd->singleton() && tadd != Type::TOP ) {
      Node *sub2 = phase->transform( new (phase->C) SubINode( in1->in(1), in2 ));
      return new (phase->C) AddINode( sub2, in1->in(2) );
    }
  }


  // Convert "x - (y+c0)" into "(x-y) - c0"
  // Need the same check as in above optimization but reversed.
  if (op2 == Op_AddI && ok_to_convert(in2, in1)) {
    Node* in21 = in2->in(1);
    Node* in22 = in2->in(2);
    const TypeInt* tcon = phase->type(in22)->isa_int();
    if (tcon != NULL && tcon->is_con()) {
      Node* sub2 = phase->transform( new (phase->C) SubINode(in1, in21) );
      Node* neg_c0 = phase->intcon(- tcon->get_con());
      return new (phase->C) AddINode(sub2, neg_c0);
    }
  }

  const Type *t1 = phase->type( in1 );
  if( t1 == Type::TOP ) return NULL;

#ifdef ASSERT
  // Check for dead loop
  if( ( op2 == Op_AddI || op2 == Op_SubI ) &&
      ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
        phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
    assert(false, "dead loop in SubINode::Ideal");
#endif

  // Convert "x - (x+y)" into "-y"
  if( op2 == Op_AddI &&
      phase->eqv( in1, in2->in(1) ) )
    return new (phase->C) SubINode( phase->intcon(0),in2->in(2));
  // Convert "(x-y) - x" into "-y"
  if( op1 == Op_SubI &&
      phase->eqv( in1->in(1), in2 ) )
    return new (phase->C) SubINode( phase->intcon(0),in1->in(2));
  // Convert "x - (y+x)" into "-y"
  if( op2 == Op_AddI &&
      phase->eqv( in1, in2->in(2) ) )
    return new (phase->C) SubINode( phase->intcon(0),in2->in(1));

  // Convert "0 - (x-y)" into "y-x"
  if( t1 == TypeInt::ZERO && op2 == Op_SubI )
    return new (phase->C) SubINode( in2->in(2), in2->in(1) );

  // Convert "0 - (x+con)" into "-con-x"
  jint con;
  if( t1 == TypeInt::ZERO && op2 == Op_AddI &&
      (con = in2->in(2)->find_int_con(0)) != 0 )
    return new (phase->C) SubINode( phase->intcon(-con), in2->in(1) );

  // Convert "(X+A) - (X+B)" into "A - B"
  if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) )
    return new (phase->C) SubINode( in1->in(2), in2->in(2) );

  // Convert "(A+X) - (B+X)" into "A - B"
  if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) )
    return new (phase->C) SubINode( in1->in(1), in2->in(1) );

  // Convert "(A+X) - (X+B)" into "A - B"
  if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) )
    return new (phase->C) SubINode( in1->in(1), in2->in(2) );

  // Convert "(X+A) - (B+X)" into "A - B"
  if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) )
    return new (phase->C) SubINode( in1->in(2), in2->in(1) );

  // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally
  // nicer to optimize than subtract.
  if( op2 == Op_SubI && in2->outcnt() == 1) {
    Node *add1 = phase->transform( new (phase->C) AddINode( in1, in2->in(2) ) );
    return new (phase->C) SubINode( add1, in2->in(1) );
  }

  return NULL;
}

//------------------------------sub--------------------------------------------
// A subtract node differences it's two inputs.
const Type *SubINode::sub( const Type *t1, const Type *t2 ) const {
  const TypeInt *r0 = t1->is_int(); // Handy access
  const TypeInt *r1 = t2->is_int();
  int32 lo = r0->_lo - r1->_hi;
  int32 hi = r0->_hi - r1->_lo;

  // We next check for 32-bit overflow.
  // If that happens, we just assume all integers are possible.
  if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
       ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
      (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
       ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
    return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen));
  else                          // Overflow; assume all integers
    return TypeInt::INT;
}

//=============================================================================
//------------------------------Ideal------------------------------------------
Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  Node *in1 = in(1);
  Node *in2 = in(2);
  uint op1 = in1->Opcode();
  uint op2 = in2->Opcode();

#ifdef ASSERT
  // Check for dead loop
  if( phase->eqv( in1, this ) || phase->eqv( in2, this ) ||
      ( op1 == Op_AddL || op1 == Op_SubL ) &&
      ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) ||
        phase->eqv( in1->in(1), in1  ) || phase->eqv( in1->in(2), in1  ) ) )
    assert(false, "dead loop in SubLNode::Ideal");
#endif

  if( phase->type( in2 ) == Type::TOP ) return NULL;
  const TypeLong *i = phase->type( in2 )->isa_long();
  // Convert "x-c0" into "x+ -c0".
  if( i &&                      // Might be bottom or top...
      i->is_con() )
    return new (phase->C) AddLNode(in1, phase->longcon(-i->get_con()));

  // Convert "(x+c0) - y" into (x-y) + c0"
  // Do not collapse (x+c0)-y if "+" is a loop increment or
  // if "y" is a loop induction variable.
  if( op1 == Op_AddL && ok_to_convert(in1, in2) ) {
    Node *in11 = in1->in(1);
    const Type *tadd = phase->type( in1->in(2) );
    if( tadd->singleton() && tadd != Type::TOP ) {
      Node *sub2 = phase->transform( new (phase->C) SubLNode( in11, in2 ));
      return new (phase->C) AddLNode( sub2, in1->in(2) );
    }
  }

  // Convert "x - (y+c0)" into "(x-y) - c0"
  // Need the same check as in above optimization but reversed.
  if (op2 == Op_AddL && ok_to_convert(in2, in1)) {
    Node* in21 = in2->in(1);
    Node* in22 = in2->in(2);
    const TypeLong* tcon = phase->type(in22)->isa_long();
    if (tcon != NULL && tcon->is_con()) {
      Node* sub2 = phase->transform( new (phase->C) SubLNode(in1, in21) );
      Node* neg_c0 = phase->longcon(- tcon->get_con());
      return new (phase->C) AddLNode(sub2, neg_c0);
    }
  }

  const Type *t1 = phase->type( in1 );
  if( t1 == Type::TOP ) return NULL;

#ifdef ASSERT
  // Check for dead loop
  if( ( op2 == Op_AddL || op2 == Op_SubL ) &&
      ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) ||
        phase->eqv( in2->in(1), in2  ) || phase->eqv( in2->in(2), in2  ) ) )
    assert(false, "dead loop in SubLNode::Ideal");
#endif

  // Convert "x - (x+y)" into "-y"
  if( op2 == Op_AddL &&
      phase->eqv( in1, in2->in(1) ) )
    return new (phase->C) SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2));
  // Convert "x - (y+x)" into "-y"
  if( op2 == Op_AddL &&
      phase->eqv( in1, in2->in(2) ) )
    return new (phase->C) SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1));

  // Convert "0 - (x-y)" into "y-x"
  if( phase->type( in1 ) == TypeLong::ZERO && op2 == Op_SubL )
    return new (phase->C) SubLNode( in2->in(2), in2->in(1) );

  // Convert "(X+A) - (X+B)" into "A - B"
  if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) )
    return new (phase->C) SubLNode( in1->in(2), in2->in(2) );

  // Convert "(A+X) - (B+X)" into "A - B"
  if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) )
    return new (phase->C) SubLNode( in1->in(1), in2->in(1) );

  // Convert "A-(B-C)" into (A+C)-B"
  if( op2 == Op_SubL && in2->outcnt() == 1) {
    Node *add1 = phase->transform( new (phase->C) AddLNode( in1, in2->in(2) ) );
    return new (phase->C) SubLNode( add1, in2->in(1) );
  }

  return NULL;
}

//------------------------------sub--------------------------------------------
// A subtract node differences it's two inputs.
const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const {
  const TypeLong *r0 = t1->is_long(); // Handy access
  const TypeLong *r1 = t2->is_long();
  jlong lo = r0->_lo - r1->_hi;
  jlong hi = r0->_hi - r1->_lo;

  // We next check for 32-bit overflow.
  // If that happens, we just assume all integers are possible.
  if( (((r0->_lo ^ r1->_hi) >= 0) ||    // lo ends have same signs OR
       ((r0->_lo ^      lo) >= 0)) &&   // lo results have same signs AND
      (((r0->_hi ^ r1->_lo) >= 0) ||    // hi ends have same signs OR
       ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
    return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
  else                          // Overflow; assume all integers
    return TypeLong::LONG;
}

//=============================================================================
//------------------------------Value------------------------------------------
// A subtract node differences its two inputs.
const Type *SubFPNode::Value( PhaseTransform *phase ) const {
  const Node* in1 = in(1);
  const Node* in2 = in(2);
  // Either input is TOP ==> the result is TOP
  const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  if( t1 == Type::TOP ) return Type::TOP;
  const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  if( t2 == Type::TOP ) return Type::TOP;

  // if both operands are infinity of same sign, the result is NaN; do
  // not replace with zero
  if( (t1->is_finite() && t2->is_finite()) ) {
    if( phase->eqv(in1, in2) ) return add_id();
  }

  // Either input is BOTTOM ==> the result is the local BOTTOM
  const Type *bot = bottom_type();
  if( (t1 == bot) || (t2 == bot) ||
      (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
    return bot;

  return sub(t1,t2);            // Local flavor of type subtraction
}


//=============================================================================
//------------------------------Ideal------------------------------------------
Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  const Type *t2 = phase->type( in(2) );
  // Convert "x-c0" into "x+ -c0".
  if( t2->base() == Type::FloatCon ) {  // Might be bottom or top...
    // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) );
  }

  // Not associative because of boundary conditions (infinity)
  if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
    // Convert "x - (x+y)" into "-y"
    if( in(2)->is_Add() &&
        phase->eqv(in(1),in(2)->in(1) ) )
      return new (phase->C) SubFNode( phase->makecon(TypeF::ZERO),in(2)->in(2));
  }

  // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes
  // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0.
  //if( phase->type(in(1)) == TypeF::ZERO )
  //return new (phase->C, 2) NegFNode(in(2));

  return NULL;
}

//------------------------------sub--------------------------------------------
// A subtract node differences its two inputs.
const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const {
  // no folding if one of operands is infinity or NaN, do not do constant folding
  if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) {
    return TypeF::make( t1->getf() - t2->getf() );
  }
  else if( g_isnan(t1->getf()) ) {
    return t1;
  }
  else if( g_isnan(t2->getf()) ) {
    return t2;
  }
  else {
    return Type::FLOAT;
  }
}

//=============================================================================
//------------------------------Ideal------------------------------------------
Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){
  const Type *t2 = phase->type( in(2) );
  // Convert "x-c0" into "x+ -c0".
  if( t2->base() == Type::DoubleCon ) { // Might be bottom or top...
    // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) );
  }

  // Not associative because of boundary conditions (infinity)
  if( IdealizedNumerics && !phase->C->method()->is_strict() ) {
    // Convert "x - (x+y)" into "-y"
    if( in(2)->is_Add() &&
        phase->eqv(in(1),in(2)->in(1) ) )
      return new (phase->C) SubDNode( phase->makecon(TypeD::ZERO),in(2)->in(2));
  }

  // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes
  // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0.
  //if( phase->type(in(1)) == TypeD::ZERO )
  //return new (phase->C, 2) NegDNode(in(2));

  return NULL;
}

//------------------------------sub--------------------------------------------
// A subtract node differences its two inputs.
const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const {
  // no folding if one of operands is infinity or NaN, do not do constant folding
  if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) {
    return TypeD::make( t1->getd() - t2->getd() );
  }
  else if( g_isnan(t1->getd()) ) {
    return t1;
  }
  else if( g_isnan(t2->getd()) ) {
    return t2;
  }
  else {
    return Type::DOUBLE;
  }
}

//=============================================================================
//------------------------------Idealize---------------------------------------
// Unlike SubNodes, compare must still flatten return value to the
// range -1, 0, 1.
// And optimizations like those for (X + Y) - X fail if overflow happens.
Node *CmpNode::Identity( PhaseTransform *phase ) {
  return this;
}

//=============================================================================
//------------------------------cmp--------------------------------------------
// Simplify a CmpI (compare 2 integers) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const {
  const TypeInt *r0 = t1->is_int(); // Handy access
  const TypeInt *r1 = t2->is_int();

  if( r0->_hi < r1->_lo )       // Range is always low?
    return TypeInt::CC_LT;
  else if( r0->_lo > r1->_hi )  // Range is always high?
    return TypeInt::CC_GT;

  else if( r0->is_con() && r1->is_con() ) { // comparing constants?
    assert(r0->get_con() == r1->get_con(), "must be equal");
    return TypeInt::CC_EQ;      // Equal results.
  } else if( r0->_hi == r1->_lo ) // Range is never high?
    return TypeInt::CC_LE;
  else if( r0->_lo == r1->_hi ) // Range is never low?
    return TypeInt::CC_GE;
  return TypeInt::CC;           // else use worst case results
}

// Simplify a CmpU (compare 2 integers) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const {
  assert(!t1->isa_ptr(), "obsolete usage of CmpU");

  // comparing two unsigned ints
  const TypeInt *r0 = t1->is_int();   // Handy access
  const TypeInt *r1 = t2->is_int();

  // Current installed version
  // Compare ranges for non-overlap
  juint lo0 = r0->_lo;
  juint hi0 = r0->_hi;
  juint lo1 = r1->_lo;
  juint hi1 = r1->_hi;

  // If either one has both negative and positive values,
  // it therefore contains both 0 and -1, and since [0..-1] is the
  // full unsigned range, the type must act as an unsigned bottom.
  bool bot0 = ((jint)(lo0 ^ hi0) < 0);
  bool bot1 = ((jint)(lo1 ^ hi1) < 0);

  if (bot0 || bot1) {
    // All unsigned values are LE -1 and GE 0.
    if (lo0 == 0 && hi0 == 0) {
      return TypeInt::CC_LE;            //   0 <= bot
    } else if (lo1 == 0 && hi1 == 0) {
      return TypeInt::CC_GE;            // bot >= 0
    }
  } else {
    // We can use ranges of the form [lo..hi] if signs are the same.
    assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid");
    // results are reversed, '-' > '+' for unsigned compare
    if (hi0 < lo1) {
      return TypeInt::CC_LT;            // smaller
    } else if (lo0 > hi1) {
      return TypeInt::CC_GT;            // greater
    } else if (hi0 == lo1 && lo0 == hi1) {
      return TypeInt::CC_EQ;            // Equal results
    } else if (lo0 >= hi1) {
      return TypeInt::CC_GE;
    } else if (hi0 <= lo1) {
      // Check for special case in Hashtable::get.  (See below.)
      if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
        return TypeInt::CC_LT;
      return TypeInt::CC_LE;
    }
  }
  // Check for special case in Hashtable::get - the hash index is
  // mod'ed to the table size so the following range check is useless.
  // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have
  // to be positive.
  // (This is a gross hack, since the sub method never
  // looks at the structure of the node in any other case.)
  if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check())
    return TypeInt::CC_LT;
  return TypeInt::CC;                   // else use worst case results
}

bool CmpUNode::is_index_range_check() const {
  // Check for the "(X ModI Y) CmpU Y" shape
  return (in(1)->Opcode() == Op_ModI &&
          in(1)->in(2)->eqv_uncast(in(2)));
}

//------------------------------Idealize---------------------------------------
Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) {
  if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) {
    switch (in(1)->Opcode()) {
    case Op_CmpL3:              // Collapse a CmpL3/CmpI into a CmpL
      return new (phase->C) CmpLNode(in(1)->in(1),in(1)->in(2));
    case Op_CmpF3:              // Collapse a CmpF3/CmpI into a CmpF
      return new (phase->C) CmpFNode(in(1)->in(1),in(1)->in(2));
    case Op_CmpD3:              // Collapse a CmpD3/CmpI into a CmpD
      return new (phase->C) CmpDNode(in(1)->in(1),in(1)->in(2));
    //case Op_SubI:
      // If (x - y) cannot overflow, then ((x - y) <?> 0)
      // can be turned into (x <?> y).
      // This is handled (with more general cases) by Ideal_sub_algebra.
    }
  }
  return NULL;                  // No change
}


//=============================================================================
// Simplify a CmpL (compare 2 longs ) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const {
  const TypeLong *r0 = t1->is_long(); // Handy access
  const TypeLong *r1 = t2->is_long();

  if( r0->_hi < r1->_lo )       // Range is always low?
    return TypeInt::CC_LT;
  else if( r0->_lo > r1->_hi )  // Range is always high?
    return TypeInt::CC_GT;

  else if( r0->is_con() && r1->is_con() ) { // comparing constants?
    assert(r0->get_con() == r1->get_con(), "must be equal");
    return TypeInt::CC_EQ;      // Equal results.
  } else if( r0->_hi == r1->_lo ) // Range is never high?
    return TypeInt::CC_LE;
  else if( r0->_lo == r1->_hi ) // Range is never low?
    return TypeInt::CC_GE;
  return TypeInt::CC;           // else use worst case results
}

//=============================================================================
//------------------------------sub--------------------------------------------
// Simplify an CmpP (compare 2 pointers) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const {
  const TypePtr *r0 = t1->is_ptr(); // Handy access
  const TypePtr *r1 = t2->is_ptr();

  // Undefined inputs makes for an undefined result
  if( TypePtr::above_centerline(r0->_ptr) ||
      TypePtr::above_centerline(r1->_ptr) )
    return Type::TOP;

  if (r0 == r1 && r0->singleton()) {
    // Equal pointer constants (klasses, nulls, etc.)
    return TypeInt::CC_EQ;
  }

  // See if it is 2 unrelated classes.
  const TypeOopPtr* p0 = r0->isa_oopptr();
  const TypeOopPtr* p1 = r1->isa_oopptr();
  if (p0 && p1) {
    Node* in1 = in(1)->uncast();
    Node* in2 = in(2)->uncast();
    AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL);
    AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL);
    if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) {
      return TypeInt::CC_GT;  // different pointers
    }
    ciKlass* klass0 = p0->klass();
    bool    xklass0 = p0->klass_is_exact();
    ciKlass* klass1 = p1->klass();
    bool    xklass1 = p1->klass_is_exact();
    int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
    if (klass0 && klass1 &&
        kps != 1 &&             // both or neither are klass pointers
        klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces
        klass1->is_loaded() && !klass1->is_interface() &&
        (!klass0->is_obj_array_klass() ||
         !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) &&
        (!klass1->is_obj_array_klass() ||
         !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) {
      bool unrelated_classes = false;
      // See if neither subclasses the other, or if the class on top
      // is precise.  In either of these cases, the compare is known
      // to fail if at least one of the pointers is provably not null.
      if (klass0->equals(klass1)) {  // if types are unequal but klasses are equal
        // Do nothing; we know nothing for imprecise types
      } else if (klass0->is_subtype_of(klass1)) {
        // If klass1's type is PRECISE, then classes are unrelated.
        unrelated_classes = xklass1;
      } else if (klass1->is_subtype_of(klass0)) {
        // If klass0's type is PRECISE, then classes are unrelated.
        unrelated_classes = xklass0;
      } else {                  // Neither subtypes the other
        unrelated_classes = true;
      }
      if (unrelated_classes) {
        // The oops classes are known to be unrelated. If the joined PTRs of
        // two oops is not Null and not Bottom, then we are sure that one
        // of the two oops is non-null, and the comparison will always fail.
        TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
        if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
          return TypeInt::CC_GT;
        }
      }
    }
  }

  // Known constants can be compared exactly
  // Null can be distinguished from any NotNull pointers
  // Unknown inputs makes an unknown result
  if( r0->singleton() ) {
    intptr_t bits0 = r0->get_con();
    if( r1->singleton() )
      return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
    return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
  } else if( r1->singleton() ) {
    intptr_t bits1 = r1->get_con();
    return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
  } else
    return TypeInt::CC;
}

static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) {
  // Return the klass node for
  //   LoadP(AddP(foo:Klass, #java_mirror))
  //   or NULL if not matching.
  if (n->Opcode() != Op_LoadP) return NULL;

  const TypeInstPtr* tp = phase->type(n)->isa_instptr();
  if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL;

  Node* adr = n->in(MemNode::Address);
  intptr_t off = 0;
  Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off);
  if (k == NULL)  return NULL;
  const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr();
  if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL;

  // We've found the klass node of a Java mirror load.
  return k;
}

static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) {
  // for ConP(Foo.class) return ConP(Foo.klass)
  // otherwise return NULL
  if (!n->is_Con()) return NULL;

  const TypeInstPtr* tp = phase->type(n)->isa_instptr();
  if (!tp) return NULL;

  ciType* mirror_type = tp->java_mirror_type();
  // TypeInstPtr::java_mirror_type() returns non-NULL for compile-
  // time Class constants only.
  if (!mirror_type) return NULL;

  // x.getClass() == int.class can never be true (for all primitive types)
  // Return a ConP(NULL) node for this case.
  if (mirror_type->is_classless()) {
    return phase->makecon(TypePtr::NULL_PTR);
  }

  // return the ConP(Foo.klass)
  assert(mirror_type->is_klass(), "mirror_type should represent a Klass*");
  return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass()));
}

//------------------------------Ideal------------------------------------------
// Normalize comparisons between Java mirror loads to compare the klass instead.
//
// Also check for the case of comparing an unknown klass loaded from the primary
// super-type array vs a known klass with no subtypes.  This amounts to
// checking to see an unknown klass subtypes a known klass with no subtypes;
// this only happens on an exact match.  We can shorten this test by 1 load.
Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
  // Normalize comparisons between Java mirrors into comparisons of the low-
  // level klass, where a dependent load could be shortened.
  //
  // The new pattern has a nice effect of matching the same pattern used in the
  // fast path of instanceof/checkcast/Class.isInstance(), which allows
  // redundant exact type check be optimized away by GVN.
  // For example, in
  //   if (x.getClass() == Foo.class) {
  //     Foo foo = (Foo) x;
  //     // ... use a ...
  //   }
  // a CmpPNode could be shared between if_acmpne and checkcast
  {
    Node* k1 = isa_java_mirror_load(phase, in(1));
    Node* k2 = isa_java_mirror_load(phase, in(2));
    Node* conk2 = isa_const_java_mirror(phase, in(2));

    if (k1 && (k2 || conk2)) {
      Node* lhs = k1;
      Node* rhs = (k2 != NULL) ? k2 : conk2;
      this->set_req(1, lhs);
      this->set_req(2, rhs);
      return this;
    }
  }

  // Constant pointer on right?
  const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr();
  if (t2 == NULL || !t2->klass_is_exact())
    return NULL;
  // Get the constant klass we are comparing to.
  ciKlass* superklass = t2->klass();

  // Now check for LoadKlass on left.
  Node* ldk1 = in(1);
  if (ldk1->is_DecodeNKlass()) {
    ldk1 = ldk1->in(1);
    if (ldk1->Opcode() != Op_LoadNKlass )
      return NULL;
  } else if (ldk1->Opcode() != Op_LoadKlass )
    return NULL;
  // Take apart the address of the LoadKlass:
  Node* adr1 = ldk1->in(MemNode::Address);
  intptr_t con2 = 0;
  Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2);
  if (ldk2 == NULL)
    return NULL;
  if (con2 == oopDesc::klass_offset_in_bytes()) {
    // We are inspecting an object's concrete class.
    // Short-circuit the check if the query is abstract.
    if (superklass->is_interface() ||
        superklass->is_abstract()) {
      // Make it come out always false:
      this->set_req(2, phase->makecon(TypePtr::NULL_PTR));
      return this;
    }
  }

  // Check for a LoadKlass from primary supertype array.
  // Any nested loadklass from loadklass+con must be from the p.s. array.
  if (ldk2->is_DecodeNKlass()) {
    // Keep ldk2 as DecodeN since it could be used in CmpP below.
    if (ldk2->in(1)->Opcode() != Op_LoadNKlass )
      return NULL;
  } else if (ldk2->Opcode() != Op_LoadKlass)
    return NULL;

  // Verify that we understand the situation
  if (con2 != (intptr_t) superklass->super_check_offset())
    return NULL;                // Might be element-klass loading from array klass

  // If 'superklass' has no subklasses and is not an interface, then we are
  // assured that the only input which will pass the type check is
  // 'superklass' itself.
  //
  // We could be more liberal here, and allow the optimization on interfaces
  // which have a single implementor.  This would require us to increase the
  // expressiveness of the add_dependency() mechanism.
  // %%% Do this after we fix TypeOopPtr:  Deps are expressive enough now.

  // Object arrays must have their base element have no subtypes
  while (superklass->is_obj_array_klass()) {
    ciType* elem = superklass->as_obj_array_klass()->element_type();
    superklass = elem->as_klass();
  }
  if (superklass->is_instance_klass()) {
    ciInstanceKlass* ik = superklass->as_instance_klass();
    if (ik->has_subklass() || ik->is_interface())  return NULL;
    // Add a dependency if there is a chance that a subclass will be added later.
    if (!ik->is_final()) {
      phase->C->dependencies()->assert_leaf_type(ik);
    }
  }

  // Bypass the dependent load, and compare directly
  this->set_req(1,ldk2);

  return this;
}

//=============================================================================
//------------------------------sub--------------------------------------------
// Simplify an CmpN (compare 2 pointers) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
  const TypePtr *r0 = t1->make_ptr(); // Handy access
  const TypePtr *r1 = t2->make_ptr();

  // Undefined inputs makes for an undefined result
  if ((r0 == NULL) || (r1 == NULL) ||
      TypePtr::above_centerline(r0->_ptr) ||
      TypePtr::above_centerline(r1->_ptr)) {
    return Type::TOP;
  }
  if (r0 == r1 && r0->singleton()) {
    // Equal pointer constants (klasses, nulls, etc.)
    return TypeInt::CC_EQ;
  }

  // See if it is 2 unrelated classes.
  const TypeOopPtr* p0 = r0->isa_oopptr();
  const TypeOopPtr* p1 = r1->isa_oopptr();
  if (p0 && p1) {
    ciKlass* klass0 = p0->klass();
    bool    xklass0 = p0->klass_is_exact();
    ciKlass* klass1 = p1->klass();
    bool    xklass1 = p1->klass_is_exact();
    int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
    if (klass0 && klass1 &&
        kps != 1 &&             // both or neither are klass pointers
        !klass0->is_interface() && // do not trust interfaces
        !klass1->is_interface()) {
      bool unrelated_classes = false;
      // See if neither subclasses the other, or if the class on top
      // is precise.  In either of these cases, the compare is known
      // to fail if at least one of the pointers is provably not null.
      if (klass0->equals(klass1)) { // if types are unequal but klasses are equal
        // Do nothing; we know nothing for imprecise types
      } else if (klass0->is_subtype_of(klass1)) {
        // If klass1's type is PRECISE, then classes are unrelated.
        unrelated_classes = xklass1;
      } else if (klass1->is_subtype_of(klass0)) {
        // If klass0's type is PRECISE, then classes are unrelated.
        unrelated_classes = xklass0;
      } else {                  // Neither subtypes the other
        unrelated_classes = true;
      }
      if (unrelated_classes) {
        // The oops classes are known to be unrelated. If the joined PTRs of
        // two oops is not Null and not Bottom, then we are sure that one
        // of the two oops is non-null, and the comparison will always fail.
        TypePtr::PTR jp = r0->join_ptr(r1->_ptr);
        if (jp != TypePtr::Null && jp != TypePtr::BotPTR) {
          return TypeInt::CC_GT;
        }
      }
    }
  }

  // Known constants can be compared exactly
  // Null can be distinguished from any NotNull pointers
  // Unknown inputs makes an unknown result
  if( r0->singleton() ) {
    intptr_t bits0 = r0->get_con();
    if( r1->singleton() )
      return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
    return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
  } else if( r1->singleton() ) {
    intptr_t bits1 = r1->get_con();
    return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
  } else
    return TypeInt::CC;
}

//------------------------------Ideal------------------------------------------
Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
  return NULL;
}

//=============================================================================
//------------------------------Value------------------------------------------
// Simplify an CmpF (compare 2 floats ) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpFNode::Value( PhaseTransform *phase ) const {
  const Node* in1 = in(1);
  const Node* in2 = in(2);
  // Either input is TOP ==> the result is TOP
  const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  if( t1 == Type::TOP ) return Type::TOP;
  const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  if( t2 == Type::TOP ) return Type::TOP;

  // Not constants?  Don't know squat - even if they are the same
  // value!  If they are NaN's they compare to LT instead of EQ.
  const TypeF *tf1 = t1->isa_float_constant();
  const TypeF *tf2 = t2->isa_float_constant();
  if( !tf1 || !tf2 ) return TypeInt::CC;

  // This implements the Java bytecode fcmpl, so unordered returns -1.
  if( tf1->is_nan() || tf2->is_nan() )
    return TypeInt::CC_LT;

  if( tf1->_f < tf2->_f ) return TypeInt::CC_LT;
  if( tf1->_f > tf2->_f ) return TypeInt::CC_GT;
  assert( tf1->_f == tf2->_f, "do not understand FP behavior" );
  return TypeInt::CC_EQ;
}


//=============================================================================
//------------------------------Value------------------------------------------
// Simplify an CmpD (compare 2 doubles ) node, based on local information.
// If both inputs are constants, compare them.
const Type *CmpDNode::Value( PhaseTransform *phase ) const {
  const Node* in1 = in(1);
  const Node* in2 = in(2);
  // Either input is TOP ==> the result is TOP
  const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);
  if( t1 == Type::TOP ) return Type::TOP;
  const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2);
  if( t2 == Type::TOP ) return Type::TOP;

  // Not constants?  Don't know squat - even if they are the same
  // value!  If they are NaN's they compare to LT instead of EQ.
  const TypeD *td1 = t1->isa_double_constant();
  const TypeD *td2 = t2->isa_double_constant();
  if( !td1 || !td2 ) return TypeInt::CC;

  // This implements the Java bytecode dcmpl, so unordered returns -1.
  if( td1->is_nan() || td2->is_nan() )
    return TypeInt::CC_LT;

  if( td1->_d < td2->_d ) return TypeInt::CC_LT;
  if( td1->_d > td2->_d ) return TypeInt::CC_GT;
  assert( td1->_d == td2->_d, "do not understand FP behavior" );
  return TypeInt::CC_EQ;
}

//------------------------------Ideal------------------------------------------
Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){
  // Check if we can change this to a CmpF and remove a ConvD2F operation.
  // Change  (CMPD (F2D (float)) (ConD value))
  // To      (CMPF      (float)  (ConF value))
  // Valid when 'value' does not lose precision as a float.
  // Benefits: eliminates conversion, does not require 24-bit mode

  // NaNs prevent commuting operands.  This transform works regardless of the
  // order of ConD and ConvF2D inputs by preserving the original order.
  int idx_f2d = 1;              // ConvF2D on left side?
  if( in(idx_f2d)->Opcode() != Op_ConvF2D )
    idx_f2d = 2;                // No, swap to check for reversed args
  int idx_con = 3-idx_f2d;      // Check for the constant on other input

  if( ConvertCmpD2CmpF &&
      in(idx_f2d)->Opcode() == Op_ConvF2D &&
      in(idx_con)->Opcode() == Op_ConD ) {
    const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant();
    double t2_value_as_double = t2->_d;
    float  t2_value_as_float  = (float)t2_value_as_double;
    if( t2_value_as_double == (double)t2_value_as_float ) {
      // Test value can be represented as a float
      // Eliminate the conversion to double and create new comparison
      Node *new_in1 = in(idx_f2d)->in(1);
      Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) );
      if( idx_f2d != 1 ) {      // Must flip args to match original order
        Node *tmp = new_in1;
        new_in1 = new_in2;
        new_in2 = tmp;
      }
      CmpFNode *new_cmp = (Opcode() == Op_CmpD3)
        ? new (phase->C) CmpF3Node( new_in1, new_in2 )
        : new (phase->C) CmpFNode ( new_in1, new_in2 ) ;
      return new_cmp;           // Changed to CmpFNode
    }
    // Testing value required the precision of a double
  }
  return NULL;                  // No change
}


//=============================================================================
//------------------------------cc2logical-------------------------------------
// Convert a condition code type to a logical type
const Type *BoolTest::cc2logical( const Type *CC ) const {
  if( CC == Type::TOP ) return Type::TOP;
  if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse
  const TypeInt *ti = CC->is_int();
  if( ti->is_con() ) {          // Only 1 kind of condition codes set?
    // Match low order 2 bits
    int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0;
    if( _test & 4 ) tmp = 1-tmp;     // Optionally complement result
    return TypeInt::make(tmp);       // Boolean result
  }

  if( CC == TypeInt::CC_GE ) {
    if( _test == ge ) return TypeInt::ONE;
    if( _test == lt ) return TypeInt::ZERO;
  }
  if( CC == TypeInt::CC_LE ) {
    if( _test == le ) return TypeInt::ONE;
    if( _test == gt ) return TypeInt::ZERO;
  }

  return TypeInt::BOOL;
}

//------------------------------dump_spec-------------------------------------
// Print special per-node info
#ifndef PRODUCT
void BoolTest::dump_on(outputStream *st) const {
  const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"};
  st->print(msg[_test]);
}
#endif

//=============================================================================
uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); }
uint BoolNode::size_of() const { return sizeof(BoolNode); }

//------------------------------operator==-------------------------------------
uint BoolNode::cmp( const Node &n ) const {
  const BoolNode *b = (const BoolNode *)&n; // Cast up
  return (_test._test == b->_test._test);
}

//-------------------------------make_predicate--------------------------------
Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) {
  if (test_value->is_Con())   return test_value;
  if (test_value->is_Bool())  return test_value;
  Compile* C = phase->C;
  if (test_value->is_CMove() &&
      test_value->in(CMoveNode::Condition)->is_Bool()) {
    BoolNode*   bol   = test_value->in(CMoveNode::Condition)->as_Bool();
    const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse));
    const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue));
    if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) {
      return bol;
    } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) {
      return phase->transform( bol->negate(phase) );
    }
    // Else fall through.  The CMove gets in the way of the test.
    // It should be the case that make_predicate(bol->as_int_value()) == bol.
  }
  Node* cmp = new (C) CmpINode(test_value, phase->intcon(0));
  cmp = phase->transform(cmp);
  Node* bol = new (C) BoolNode(cmp, BoolTest::ne);
  return phase->transform(bol);
}

//--------------------------------as_int_value---------------------------------
Node* BoolNode::as_int_value(PhaseGVN* phase) {
  // Inverse to make_predicate.  The CMove probably boils down to a Conv2B.
  Node* cmov = CMoveNode::make(phase->C, NULL, this,
                               phase->intcon(0), phase->intcon(1),
                               TypeInt::BOOL);
  return phase->transform(cmov);
}

//----------------------------------negate-------------------------------------
BoolNode* BoolNode::negate(PhaseGVN* phase) {
  Compile* C = phase->C;
  return new (C) BoolNode(in(1), _test.negate());
}


//------------------------------Ideal------------------------------------------
Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) {
  // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)".
  // This moves the constant to the right.  Helps value-numbering.
  Node *cmp = in(1);
  if( !cmp->is_Sub() ) return NULL;
  int cop = cmp->Opcode();
  if( cop == Op_FastLock || cop == Op_FastUnlock || cop == Op_FlagsProj) return NULL;
  Node *cmp1 = cmp->in(1);
  Node *cmp2 = cmp->in(2);
  if( !cmp1 ) return NULL;

  // Constant on left?
  Node *con = cmp1;
  uint op2 = cmp2->Opcode();
  // Move constants to the right of compare's to canonicalize.
  // Do not muck with Opaque1 nodes, as this indicates a loop
  // guard that cannot change shape.
  if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 &&
      // Because of NaN's, CmpD and CmpF are not commutative
      cop != Op_CmpD && cop != Op_CmpF &&
      // Protect against swapping inputs to a compare when it is used by a
      // counted loop exit, which requires maintaining the loop-limit as in(2)
      !is_counted_loop_exit_test() ) {
    // Ok, commute the constant to the right of the cmp node.
    // Clone the Node, getting a new Node of the same class
    cmp = cmp->clone();
    // Swap inputs to the clone
    cmp->swap_edges(1, 2);
    cmp = phase->transform( cmp );
    return new (phase->C) BoolNode( cmp, _test.commute() );
  }

  // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)".
  // The XOR-1 is an idiom used to flip the sense of a bool.  We flip the
  // test instead.
  int cmp1_op = cmp1->Opcode();
  const TypeInt* cmp2_type = phase->type(cmp2)->isa_int();
  if (cmp2_type == NULL)  return NULL;
  Node* j_xor = cmp1;
  if( cmp2_type == TypeInt::ZERO &&
      cmp1_op == Op_XorI &&
      j_xor->in(1) != j_xor &&          // An xor of itself is dead
      phase->type( j_xor->in(1) ) == TypeInt::BOOL &&
      phase->type( j_xor->in(2) ) == TypeInt::ONE &&
      (_test._test == BoolTest::eq ||
       _test._test == BoolTest::ne) ) {
    Node *ncmp = phase->transform(new (phase->C) CmpINode(j_xor->in(1),cmp2));
    return new (phase->C) BoolNode( ncmp, _test.negate() );
  }

  // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)".
  // This is a standard idiom for branching on a boolean value.
  Node *c2b = cmp1;
  if( cmp2_type == TypeInt::ZERO &&
      cmp1_op == Op_Conv2B &&
      (_test._test == BoolTest::eq ||
       _test._test == BoolTest::ne) ) {
    Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int()
       ? (Node*)new (phase->C) CmpINode(c2b->in(1),cmp2)
       : (Node*)new (phase->C) CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR))
    );
    return new (phase->C) BoolNode( ncmp, _test._test );
  }

  // Comparing a SubI against a zero is equal to comparing the SubI
  // arguments directly.  This only works for eq and ne comparisons
  // due to possible integer overflow.
  if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) &&
        (cop == Op_CmpI) &&
        (cmp1->Opcode() == Op_SubI) &&
        ( cmp2_type == TypeInt::ZERO ) ) {
    Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(1),cmp1->in(2)));
    return new (phase->C) BoolNode( ncmp, _test._test );
  }

  // Change (-A vs 0) into (A vs 0) by commuting the test.  Disallow in the
  // most general case because negating 0x80000000 does nothing.  Needed for
  // the CmpF3/SubI/CmpI idiom.
  if( cop == Op_CmpI &&
      cmp1->Opcode() == Op_SubI &&
      cmp2_type == TypeInt::ZERO &&
      phase->type( cmp1->in(1) ) == TypeInt::ZERO &&
      phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) {
    Node *ncmp = phase->transform( new (phase->C) CmpINode(cmp1->in(2),cmp2));
    return new (phase->C) BoolNode( ncmp, _test.commute() );
  }

  //  The transformation below is not valid for either signed or unsigned
  //  comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE.
  //  This transformation can be resurrected when we are able to
  //  make inferences about the range of values being subtracted from
  //  (or added to) relative to the wraparound point.
  //
  //    // Remove +/-1's if possible.
  //    // "X <= Y-1" becomes "X <  Y"
  //    // "X+1 <= Y" becomes "X <  Y"
  //    // "X <  Y+1" becomes "X <= Y"
  //    // "X-1 <  Y" becomes "X <= Y"
  //    // Do not this to compares off of the counted-loop-end.  These guys are
  //    // checking the trip counter and they want to use the post-incremented
  //    // counter.  If they use the PRE-incremented counter, then the counter has
  //    // to be incremented in a private block on a loop backedge.
  //    if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd )
  //      return NULL;
  //  #ifndef PRODUCT
  //    // Do not do this in a wash GVN pass during verification.
  //    // Gets triggered by too many simple optimizations to be bothered with
  //    // re-trying it again and again.
  //    if( !phase->allow_progress() ) return NULL;
  //  #endif
  //    // Not valid for unsigned compare because of corner cases in involving zero.
  //    // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an
  //    // exception in case X is 0 (because 0-1 turns into 4billion unsigned but
  //    // "0 <=u Y" is always true).
  //    if( cmp->Opcode() == Op_CmpU ) return NULL;
  //    int cmp2_op = cmp2->Opcode();
  //    if( _test._test == BoolTest::le ) {
  //      if( cmp1_op == Op_AddI &&
  //          phase->type( cmp1->in(2) ) == TypeInt::ONE )
  //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt );
  //      else if( cmp2_op == Op_AddI &&
  //         phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 )
  //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt );
  //    } else if( _test._test == BoolTest::lt ) {
  //      if( cmp1_op == Op_AddI &&
  //          phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 )
  //        return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le );
  //      else if( cmp2_op == Op_AddI &&
  //         phase->type( cmp2->in(2) ) == TypeInt::ONE )
  //        return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le );
  //    }

  return NULL;
}

//------------------------------Value------------------------------------------
// Simplify a Bool (convert condition codes to boolean (1 or 0)) node,
// based on local information.   If the input is constant, do it.
const Type *BoolNode::Value( PhaseTransform *phase ) const {
  return _test.cc2logical( phase->type( in(1) ) );
}

//------------------------------dump_spec--------------------------------------
// Dump special per-node info
#ifndef PRODUCT
void BoolNode::dump_spec(outputStream *st) const {
  st->print("[");
  _test.dump_on(st);
  st->print("]");
}
#endif

//------------------------------is_counted_loop_exit_test--------------------------------------
// Returns true if node is used by a counted loop node.
bool BoolNode::is_counted_loop_exit_test() {
  for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
    Node* use = fast_out(i);
    if (use->is_CountedLoopEnd()) {
      return true;
    }
  }
  return false;
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute sqrt
const Type *SqrtDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  if( d < 0.0 ) return Type::DOUBLE;
  return TypeD::make( sqrt( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute cos
const Type *CosDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_cos( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute sin
const Type *SinDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_sin( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute tan
const Type *TanDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_tan( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute log
const Type *LogDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_log( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute log10
const Type *Log10DNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_log10( d ) );
}

//=============================================================================
//------------------------------Value------------------------------------------
// Compute exp
const Type *ExpDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d = t1->getd();
  return TypeD::make( StubRoutines::intrinsic_exp( d ) );
}


//=============================================================================
//------------------------------Value------------------------------------------
// Compute pow
const Type *PowDNode::Value( PhaseTransform *phase ) const {
  const Type *t1 = phase->type( in(1) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t1->base() != Type::DoubleCon ) return Type::DOUBLE;
  const Type *t2 = phase->type( in(2) );
  if( t2 == Type::TOP ) return Type::TOP;
  if( t2->base() != Type::DoubleCon ) return Type::DOUBLE;
  double d1 = t1->getd();
  double d2 = t2->getd();
  return TypeD::make( StubRoutines::intrinsic_pow( d1, d2 ) );
}

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